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oe1(光电查) - 科学论文

113 条数据
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  • [IEEE 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - Poznan, Poland (2018.9.19-2018.9.21)] 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - On the influence of the image normalization scheme on texture classification accuracy

    摘要: Texture can be a very rich source of information about the image. Texture analysis finds applications, among other things, in biomedical imaging. One of the widely used methods of texture analysis is the Gray Level Co-occurrence Matrix (GLCM). Texture analysis using the GLCM method is most often carried out in several stages: determination of areas of interest, normalization, calculation of the GLCM, extraction of features, and finally, the classification. Values of the GLCM based features depend on the choice of the normalization method, which was examined in this work. The normalization is necessary, since acquired images often suffer from noise and intensity artifacts. Certainly, the normalization will not eliminate these two effects, however it was demonstrated, that its application improves texture analysis accuracy. The aim of the work was to analyze the influence of different normalization methods on the discriminating ability of features estimated from the GLCM. The analysis was performed both for Brodatz textures and real magnetic resonance data. Brodatz textures were corrupted by three types of distortion: intensity nonuniformity, Gaussian noise and Rician Noise. Three types of normalizations were tested: min?max, 1?99% and +/?3σ.

    关键词: normalization,classification,image processing,texture analysis,GLCM

    更新于2025-09-23 15:23:52

  • Compressive Phase Retrieval Realized by Combining Generalized Approximate Message Passing with Cartoon-Texture Model

    摘要: Generalized approximate message passing (GAMP) can be applied to compressive phase retrieval (CPR) with excellent phase-transition behavior. In this paper, we introduced the cartoon-texture model into the denoising-based phase retrieval GAMP(D-prGAMP), and proposed a cartoon-texture model based D-prGAMP (C-T D-prGAMP) algorithm. Then, based on experiments and analyses on the variations of the performance of D-PrGAMP algorithms with iterations, we proposed a 2-stage D-prGAMP algorithm, which makes tradeoffs between the C-T D-prGAMP algorithm and general D-prGAMP algorithms. Finally, facing the non-convergence issues of D-prGAMP, we incorporated adaptive damping to 2-stage D-prGAMP, and proposed the adaptively damped 2-stage D-prGAMP (2-stage ADD-prGAMP) algorithm. Simulation results show that, runtime of 2-stage D-prGAMP is relatively equivalent to that of BM3D-prGAMP, but 2-stage D-prGAMP can achieve higher image reconstruction quality than BM3D-prGAMP. 2-stage ADD-prGAMP spends more reconstruction time than 2-stage D-prGAMP and BM3D-prGAMP. But, 2-stage ADD-prGAMP can achieve PSNRs 0.2 ~ 3 dB higher than those of 2-stage D-prGAMP and 0.3 ~ 3.1 dB higher than those of BM3D-prGAMP.

    关键词: cartoon-texture model,generalized approximate message passing,adaptive damping,compressive phase retrieval

    更新于2025-09-23 15:22:29

  • [IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Realistic Texture Reconstruction Incorporating Spectrophotometric Color Correction

    摘要: With the proliferation of high resolution 3D scanners, the quality of recorded 3D models has greatly improved. Nonetheless, while geometric fidelity is important, color information is still required to achieve photo-realistic 3D models. In this regard, texture reconstruction techniques combine color images from several views in order to optimally color the mesh of a 3D model. Nonetheless, a major challenge that is often overlooked by existing approaches is the technical limitations of color acquisition devices that lead to erroneously colored 3D models. In this paper, a novel technique is presented that formulates texture reconstruction as an optimization problem incorporating a color correction term in its objective function. The underlying rationale is to exploit external to the 3D scanner color measurements that can be available from more reliable sensors such as a UV-VIS spectrometer. Such measurements are often available for objects of high aesthetic value such as artworks of cultural heritage objects. Through experimental evaluation of our method on a real painting we demonstrate the superiority of the proposed technique, compared to state-of-the-art texture reconstruction, providing a reliable representation of the artworks appearance both in terms of numerical accuracy and visual observation.

    关键词: cultural heritage,3D reconstruction,UV-VIS spectrometer,color correction,Texture reconstruction

    更新于2025-09-23 15:22:29

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Estimation of Forest Parameters Combining Multisensor High Resolution Remote Sensing Data

    摘要: Forest monitoring is a major issue to carry out energetic and environmental policies. Actual context in spaceborne remote sensing data is very promising. Our study aims to test the ability of SAR, optical and textural data to estimate forest parameters (biomass, height, diameter and density), and to evaluate the improvement of combining these remote sensing data. We worked on monospecific pine forest stands. The first results highlighted the synergy between SAR and spatial texture informations. Sentinel-1 C-band SAR data is very promising for the estimation of forest parameters in monospecifics stands. Biomass was estimated with 29.4% relative error (20.7 tons/ha) and height with 14.6% (2.1m) combining four SAR and optical sensors.

    关键词: Forest,biomass,texture,SAR,optical

    更新于2025-09-23 15:22:29

  • [IEEE 2017 International Conference on Computational Science and Computational Intelligence (CSCI) - Las Vegas, NV, USA (2017.12.14-2017.12.16)] 2017 International Conference on Computational Science and Computational Intelligence (CSCI) - Estimation of Illumination Map from Dermoscopy Images for Extracting Differential Structures Using Gabor Local Mesh Patterns

    摘要: Melanoma is the most deadly form of skin cancer and its incidence rate is significantly increasing. The design of an assisted diagnosis system for the detection of melanoma is a challenging task involving various steps related to computer vision. Researchers have concluded that the accurate identification of melanoma requires robust preprocessing steps on dermoscopy images including hair removal, illumination correction etc., that can help in a better detection of melanoma. In this paper, we propose a novel illumination correction algorithm followed by robust feature extraction from dermoscopy images, leading to a better identification of cancer. Illumination correction is based on statistical estimation of illumination content in the images, followed by the extraction of differential structures using a combination of Gabor filtering followed by extracting local mesh patterns, which exhibit physiological significance based on various clinical rules for detecting melanoma. Our experiments show that the proposed technique outperforms all the other methods that have been considered in this paper.

    关键词: Texture analysis,Optimization,Pattern recognition,Gabor filters,Melanoma

    更新于2025-09-23 15:22:29

  • [IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Texture and Intensity Based Land Cover Classification in Germany from Multi-Orbit & Multi-Temporal Sentinel-L Images

    摘要: Land cover information is vital for ecosystem management, to find biodiversity indicators and for sustainable development. The launch of the Sentinel-1 satellites provide large amounts of Synthetic Aperture Radar (SAR) data that can be used for the extraction and classification of land cover. This study presents a preliminary method for land cover classification using SAR amplitude and textural features and by combining multi-temporal images from ascending and descending orbits. The texture parameters contrast, entropy, homogeneity and variance were investigated. The rules of the SAR-LC classifier, designed and implemented at the Federal Agency for Cartography and Geodesy in Frankfurt, were optimised to include textual information for processing the multi-temporal SAR images. The results for land cover classification of images from 2017 for the area around Berlin in Germany are reported along with their classification efficiencies.

    关键词: Land cover classification,Germany,Copernicus,Sentinel-1,object based classification,texture

    更新于2025-09-23 15:21:21

  • True spin and pseudo spin entanglement around Dirac Points in graphene with Rashba spin–orbit interaction

    摘要: We analytically obtained the Schmidt decomposition of the entangled state between the pseudo spin and the true spin in graphene with Rashba spin–orbit coupling. The entangled state has the standard form of the Bell state, where the SU(2) spin symmetry is broken. These states can be explicitly expressed as the superposition of two nonorthogonal, but mirror symmetrical spin states entangled with the pseudo spin states. Because of the closely locking between the pseudo spin and the true spin, it is found that the orbit curve in the spin-polarization parameter space for the fixed equi-energy contour around Dirac points has the same shape as the δk-contour. Due to the spin–orbit coupling that cause the topological transition in the local geometry of the dispersion relation, the new equi-energy contours around the new emergent Dirac Points can be obtained by squeezing the one around the original Dirac point. The spin texture in the momentum space around the Dirac points is analyzed under the Rashba spin–orbit interaction and it is found that the orientation of the spin polarization at each crystal momentum k is independent of the Rashba coupling strength.

    关键词: Spin texture,Entangled spin states,Rashba spin–orbit interaction

    更新于2025-09-23 15:21:21

  • Effects of laser scanning strategies on selective laser melting of pure tungsten

    摘要: Three types of scanning strategies, including the chessboard scanning strategy, the zigzag scanning strategy and the remelting scanning strategy, were conducted to study the effects of scanning strategies on surface morphology, microstructure, mechanical properties and the grain orientation of selective laser melted pure tungsten. The results showed that the pores and cracks were main defects in SLM-processed tungsten parts. The pores could be eliminated using the remelting scanning strategy. However, the cracks seemed to be inevitable regardless of the applied scanning strategies. The microstructures of SLM-processed tungsten were columnar grains and showed strong epitaxial growth along the building direction. A compressive strength of 923 MPa with an elongation of 7.7% was obtained when the zigzag scanning strategy was applied, which was the highest among the three scanning strategies. By changing the scanning strategies, the texture of SLM-processed tungsten in the direction of processing could be changed.

    关键词: microstructure,texture,scanning strategy,compressive strength,pure tungsten,selective laser melting

    更新于2025-09-23 15:21:01

  • Influence of soil texture on the estimation of bare soil moisture content using MODIS images

    摘要: Spectral behaviour of soil is strongly influenced by the soil texture as well as its nutrient content. Many attempts have so far been made to assess the soil moisture using soil reflectance in different bands of satellite images. In this paper, the investigations showed that the coarse texture soils did not show a profound relationship with the reflectance values that was in part due to its weak water storage capacity. Fine texture soils, on the contrary, showed better results which could be attributed to their higher water storage capacity and the capillary phenomenon. Finally, a linear regression model made of a combination of Land Surface Temperature (LST), Normalized Difference Water Index (NDWI) and Visible and Short-wave infrared Drought Index (VSDI) indices was proposed. The suggested method has improved the accuracy of the soil moisture content estimation up to 1% in general and the medium texture soil in particular. The results were compared with the performance of seven conventional soil moisture estimators method all using the Moderate Resolution Imaging Spectroradiometer (MODIS) data.

    关键词: Soil moisture content,MODIS,soil texture,US-SCAN

    更新于2025-09-23 15:21:01

  • Pathologic stratification of operable lung adenocarcinoma using radiomics features extracted from dual energy CT images

    摘要: Purpose: To evaluate the usefulness of surrogate biomarkers as predictors of histopathologic tumor grade and aggressiveness using radiomics data from dual-energy computed tomography (DECT), with the ultimate goal of accomplishing stratification of early-stage lung adenocarcinoma for optimal treatment. Results: Pathologic grade was divided into grades 1, 2, and 3. Multinomial logistic regression analysis revealed i-uniformity and 97.5th percentile CT attenuation value as independent significant factors to stratify grade 2 or 3 from grade 1. The AUC value calculated from leave-one-out cross-validation procedure for discriminating grades 1, 2, and 3 was 0.9307 (95% CI: 0.8514–1), 0.8610 (95% CI: 0.7547–0.9672), and 0.8394 (95% CI: 0.7045–0.9743), respectively. Materials and Methods: A total of 80 patients with 91 clinically and radiologically suspected stage I or II lung adenocarcinoma were prospectively enrolled. All patients underwent DECT and F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT, followed by surgery. Quantitative CT and PET imaging characteristics were evaluated using a radiomics approach. Significant features for a tumor aggressiveness prediction model were extracted and used to calculate diagnostic performance for predicting all pathologic grades. Conclusions: Quantitative radiomics values from DECT imaging metrics can help predict pathologic aggressiveness of lung adenocarcinoma.

    关键词: heterogeneity,dual energy CT,lung adenocarcinoma,radiomics,texture analysis

    更新于2025-09-23 15:21:01